(1) Field of the Invention
The invention relates to reduction of drag, and its attendant advantages for marine surface vessels, and is directed more particularly to the reduction of drag caused by additional hulls in multi-hull vessels, such as trimarans and pentamarans.
(2) Description of the Prior Art
Multi-hull surface vessels, such as trimarans and pentamarans, are used for civilian and military applications. A multi-hull design provides the advantages of vessel stability at high speeds and increased deck space. In a typical trimaran, the multi-hulls or lateral hulls are substantially smaller than the main hull and have a substantially smaller subsurface area.
While a multi-hull vessel offers the advantages set forth above, the presence of a plurality of hulls increases the drag forces of the vessel, thereby requiring more power to gain the high speeds desired.
The theoretical advantages of encompassing a hull with microbubbles to reduce drag are known and have been realized in laboratories with model ships operating at modest speeds. However, the use of microbubbles with full-sized vessels has generally been unsuccessful because the air/gas flow required for encompassing the sides of full-sized hulls is too large. A large air/gas flow requires large air/gas compressors, or the like. Further, the presence of microbubbles reduces the effectiveness of exterior propulsion units, such as the vessel's propellers.
As such, there is a need to eliminate the increased drag of a multi-hull vessel, preferably through efficient microbubble generation, so that the advantages of such vessels may be exploited to a greater degree.